Cost Optimized Redundant Power Supply with Dual AC Inputs

1. An apparatus for supplying redundant power, comprising: a plurality of power units, each of the plurality of power units comprising: first and second alternating current (AC) front ends, and a direct current (DC) back end; an AC input of the first AC front end is adapted for connection to a first AC power source, and an AC input of the second AC front end is adapted for connection to a second AC power source; a DC output of the first AC front end and a DC output of the second AC front end are coupled to a DC input of the DC back end; DC outputs of the DC back ends of the plurality of power units are coupled together for supplying DC power to a load; and wherein each of the first and second AC front ends has an available power capacity of TRP/(N+1) and each of the DC back ends has an available power capacity of TRP/N, wherein TRP is total redundant power and N is the number of non-redundant power units, and wherein the number of non-redundant power units is the total number of power units in the plurality of power units less one.

2. The apparatus according to claim 1 , wherein the DC outputs of the first and second AC front ends are isolated from each other.

3. The apparatus according to claim 2 , wherein each DC output of the first and second AC front ends is coupled to the DC input of the DC back end with a diode.

4. The apparatus according to claim 1 , wherein each of the first and second AC front ends comprises an AC-to-DC converter.

5. The apparatus according to claim 4 , wherein each of the first and second AC front ends further comprises an electromagnetic interference (EMI) filter.

6. The apparatus according to claim 4 , wherein each of the first and second AC front ends further comprises a power factor correction circuit.

7. The apparatus according to claim 1 , wherein the DC back end is a DC-to-DC switching power converter.

8. The apparatus according to claim 1 , wherein the DC back end supplies a plurality of DC output voltages.

9. The apparatus according to claim 1 , wherein the load is at least one subsystem of an information handling system.

10. A method for supplying redundant power, said method comprising the steps of: supplying a plurality of power units, each of the plurality of power units comprising first and second alternating current (AC) front ends, and a direct current (DC) back end, wherein a DC output of the first AC front end and a DC output of the second AC front end are coupled to a DC input of the DC back end, wherein each of the first and second AC front ends has an available power capacity of TRP/(N+1) and each of the DC back ends has an available power capacity of TRP/N, wherein TRP is total redundant power and N is the number of non-redundant power units, and wherein the number of non-redundant power units is the total number of power units in the plurality of power units less one; connecting an input of the first AC front end to a first AC power source; connecting an input of the second AC front end to a second AC power source; and connecting together DC outputs of the DC back ends of the plurality of power units for supplying DC power to a load.

11. The method according to claim 10 , further comprising the step of isolating the DC outputs of the first and second AC front ends from each other.

12. The method according to claim 11 , wherein each DC output of the first and second AC front ends is coupled to the DC input of the DC back end with a diode.

13. The method according to claim 10 , further comprising the step of filtering electromagnetic interference (EMI) at each of the first and second AC front ends of the plurality of power units.

14. The method according to claim 10 , further comprising the step of correcting power factor at each of the first and second AC front ends of the plurality of power units.

15. An information handling system, said system comprising: a plurality of subsystems; and a redundant power for powering the plurality of subsystems, wherein the redundant power supply comprises: a plurality of power units, each of the plurality of power units comprising: first and second alternating current (AC) front ends, and a direct current (DC) back end; an AC input of the first AC front end connected to a first AC power source, and an AC input of the second AC front end connected to a second AC power source, wherein each of the first and second AC front ends has an available power capacity of TRP/(N+1) and each of the DC back ends has an available power capacity of TRP/N, wherein TRP is total redundant power and N is the number of non-redundant power units, and wherein the number of non-redundant power units is the total number of power units in the plurality of power units less one; a DC output of the first AC front end and a DC output of the second AC front end are coupled to a DC input of the DC back end; and DC outputs of the DC back ends of the plurality of power units are coupled together for supplying DC power the plurality of subsystems.

16. The information handling system according to claim 15 , wherein the DC outputs of the first and second AC front ends are isolated from each other.